Recently, thermoelectric conversion elements have attracted an attention from the viewpoints of CO2 reduction and environmental protection. Using the thermoelectric conversion elements may enable thermal energy which has been a waste to be converted to electric energy for reuse. Since an output voltage of a single thermoelectric conversion element is low, a thermoelectric conversion module generally used is made by connecting a plurality of thermoelectric conversion elements in series.
A common thermoelectric conversion module has a structure in which many semiconductor blocks (hereinafter referred to as p-type semiconductor blocks) made of a p-type thermoelectric conversion material and many semiconductor blocks (hereinafter referred to as n-type semiconductor blocks) made of an n-type thermoelectric conversion material are held between two heat transfer plates. The p-type semiconductor blocks and the n-type semiconductor blocks are alternately arranged in the in-plane direction of the heat transfer plates and are connected in series through metal terminals disposed across each adjacent semiconductor blocks. An extraction electrode is connected to each of both ends of the serially-connected semiconductor blocks.
In the above-described thermoelectric conversion module, when a temperature difference is given to the two heat transfer plates, a potential difference is generated between the p-type semiconductor blocks and the n-type semiconductor blocks due to the Seebeck effect, which may enable electric power to be taken from the extraction electrodes. In addition, when a current is flowed through a thermoelectric conversion module with a pair of the extraction electrodes connected with a power source, heat may be transferred from one heat transfer plate to the other due to the Peltier effect.
In a general thermoelectric conversion module, as described above, a large number (several tens to several hundreds pairs) of p-type semiconductor blocks and n-type semiconductor blocks are used. Achieving a thermoelectric conversion module with a smaller size and higher performance uses a technique to miniaturize the p-type semiconductor blocks and the n-type semiconductor blocks as well as a technique to electrically connect these semiconductor blocks with each other.
According to a conventional common method of forming a thermoelectric conversion module, a semiconductor substrate (a thermoelectric conversion material substrate) is cut into a large number of semiconductor blocks by a dicing saw and these semiconductor blocks are arranged on a heat transfer plate. In addition, a metal terminal to electrically connect the semiconductor blocks with each other is formed of a metal thin film or a conductive paste.    PATENT DOCUMENT 1: Japanese Laid-open Patent Publication No. 08-43555    PATENT DOCUMENT 2: Japanese Laid-open Patent Publication No. 2004-288819    PATENT DOCUMENT 3: Japanese Laid-open Patent Publication No. 2005-5526    PATENT DOCUMENT 4: Japanese Laid-open Patent Publication No. 2005-19767
To manufacture a conventional thermoelectric conversion module, a process of cutting a semiconductor substrate into a large number of semiconductor blocks, a process of forming metal terminals, and a process of electrically connecting the semiconductor blocks with the metal terminals. This increases the number of manufacturing processes and thus increases a production cost.